SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4a68bf0f73e67eac5e8826a5e4823f3ae7ffc9379d9591f7b7ef93e3e3e3fd5' 
  AND token = 'd4ygmV/f2iBHbmBmrG0+Nxdc8rZoV1uAtKcFg8q1ycg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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