SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '073c228dee9aa709812cbab59f862bcd0be22981dcebcb978ff531f37bf38fac' 
  AND token = 'cWieXQYf+zcuu2kZm7uMreR6ZjWdmXNGAy3DVWDy6xI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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