SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84539bb0a048ec0fb843069a7b2316943663e260f970d72e9cf41ab2465b3add' 
  AND token = 'A/9nMK0ORj0CcLA6uYN5krLp7wVCzjXVWgnrQCrmLqE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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