SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4ddab49f7e587f07db8afa4ec8fb129ccf6528cfcd2638f3e90fe249359b51f9' 
  AND token = '8HoahI4tPtZJ2lA/VYZ21jVNDYji1sUFXB6n+RYSVUM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}