SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3c968f40fcf5b5ca7902b49b97367a08f8c4ba2c10a2564146f0d9535f8dff76' 
  AND token = 'ZeuQ89hsUjqw3zOzTy7Mgeh0mZyaFYSIIEQOnumXltA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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