SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c1f122377ce99fce367c6641d7a14d2b0ffd8da12c046f2f955916b2d1d1358' 
  AND token = 'VqIO9jO7unUwZcU6r0yAq87LEXpqfBVjhfms+4+1wLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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