SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8dde1a46299e957c2fc70ac96f653b191729cc08174fdba45a1b61c6ebb4c5f6' 
  AND token = '5z1V1B1LL7kJxKJpb/80Z2gqEILHNmVdqL4Q+8Xt62I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}