SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cb7c532279ed0197c7a5b57d6c6d38076e46488e8ca5f820acdd40345f453c4' 
  AND token = '91KwPd0Sg9RKJLoqOfhOCkugfBH7zBCugtGZT11oKQM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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