SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3658c4824cf0b98c7ace13cb90b5847802c1eb843959013a331c16a958cf6442' 
  AND token = 'Q9rfZZoLAl3J86IFmzPzJN3Gvix3ViZ0sskSIMyRmmQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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