SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9f093717bc88950868119701a6d2cccfc987a02888da92fa1c05131cb74e292' 
  AND token = '6Bv6dAUbmbKkCopR7a9qEn0PuMwM24aJrdWp5m3dvK8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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