SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f3a1c6228a306742677f9083bfe358dd389afdbf9d014560baa6638d61eeb3d' 
  AND token = 'J8doc/VshT0c5jF+468VypBJSwX3vuwEuo8p4Y+rsgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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