SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6fd6e0efaa1aa4599ca2cbf9f3046db3f3fcfee4eca7887a76692b408b56b022' 
  AND token = '/63bv6kLgkNXehOxxKVuZrDd7ddVkF7tix+3uNtpxIY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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