SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0fccdeedf7f60c3f485aace1769a48edff259a7cf188518a0e43bda6f83b6912' 
  AND token = '4TzsNT5d4VfPAsIo3xSVnJiqHZIp/YfHIh0+NJvtj6Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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