SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4d6d7a79a7703a228a941462d909a7258f94f0a25d796fded94ff1dc4142865e' 
  AND token = 'BiuYvRgOft8zNAtsNCGCtMQ545kiM9LPqJwgND1NRaE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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