SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'defc470d903dfecc140570ab226a0600c539e571e7bc3529a3325ff09eacfd3f' 
  AND token = '6BBxXjrhaGSYSmnnJhmf1yMha8IyKBimKI8waOLC4p4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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