SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '87ffa937560f48f04236d6230ad1cacf5c4f8c65fd880b564f087ad83f7ac5f5' 
  AND token = 'PHLR6LuDjCtsSgojLNqOEhLdMu/kQP1jsygEPg2RA1g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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