SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5590eaeb9463549e5221fecaf159c376d5c4b03d8db60bd70cc2e23caa9a27c2' 
  AND token = 'I2DBSQAzUJuIRoXM3Kd5xlH1sfPx1CsSoD5li91+5Lw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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