SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f0c9d8fd875522f329544b598da8f3a626343fa9a2c7019e2cc1867ddfce873c' 
  AND token = 'FIJaZfjhmM4ztYWz7QwVjDNUs0Cv54Pux+nFQqfE5mg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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