SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f945db235483acada94cb112b665cc932cb07e3d4964cbf47b669c469604b6a3' 
  AND token = 'GG2IpujkRWBXnBQXGJGo/zatKiEiQZeh6faxJWR7KhY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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