SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3455747e2a23d0b8a8920f59af7902745404eea180f73eb5f3c6c86075d8d93c' 
  AND token = 'u3Jie2APPoLflXS1XgRcbmuqFf1JjTYX9Wiv59ATUD4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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