SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '693724da57c88368dc4071b512cd1d090f291e1d7da802c269f328025f1947d9' 
  AND token = '0bArcPXvvebRbq+ZIBoDQgoof9UST3g7gQVoiu8sQ+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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