SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b4bf53e70bd37fe0239f76d14f4c3087f999ecb409bbb518a6631e6ed04eb41' 
  AND token = 'THeQ0TLzUhttwiluAqIK36lGBOgtoCxhjYJ4iFMSNns=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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