SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e2cc350e102a60f340d75e1dac8fa093b2c9d4897995c1f234325234956a99e' 
  AND token = 'nmyaOhxaDeojssyud7LdPxyyxHcpegU0i718/qSaxzA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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