SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7f0fa222334a1448312a214d75bf5a315e8437f76df5db68dfd6f8212e32c41a' 
  AND token = 'SYdCdWAJJL1mQmBa10FGs0MM+yzd5+wuU+wYtZHyO7g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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