SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5f478ea677427bf340f30cb2a0c41f16dcf09576d5cd9797f560222a9fc3ea0e' 
  AND token = 'LBQSMo9R8kogLyllxXCdNWsI8iq7doid48DSJlJtrXU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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