SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9be18d98da0699bfd3a65a1ad7fd5831acc755278e4e0ec9f93bb1aceb7b25d7' 
  AND token = 'aHLvgcTWgXc/kSr1BIJrsTE/mZk6TH+hlVeTSOwmYuU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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