SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9c7a5d4996086926afefa0dd627589f18f02c9a4ff007494532e01f94bae52a' 
  AND token = 'cm6jzpaMz35a0iSIqQBL+cnFojWeCKZqFieRf6YbYEQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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