SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c978539fd8ab191c41269597217ee81fa27441e240019f25e6bc701476322dad' 
  AND token = 'wKokDPRM3TXZVKZlUosJND4nBw+5ANGcyRR18bep3GY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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