SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18ac6f5380a2056759eba3335ab0491e6aaf696d5f4725d33711027fb9cba921' 
  AND token = 'HPj2XmyeAvPqgMdeyiPOosEExeUjb3uko4IPIHJgkNk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00040

JSON explain

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