SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7924dfd61301eb72cc4818cac1f81690c1318323b33842851e0512f3aee211ed' 
  AND token = 'V27QmOPOTkjeHKaejkjuAsp54GKxh7HHqwSyLUxqwhM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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