SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70c25af012ba5214547b4054c325ec643481ef10afcb4ae732f10e35be3df08e' 
  AND token = 'SYiZ1UqW/nnB/C+WwlRNj2vP78N14nvfb5SNm+TBOa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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