SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c2073e015f67f4048a55aad7be08e6f41da1712df44b5162e7e3cae2495912db' 
  AND token = 'XBha7RmtjPG/h5iQfVIA1awPmn2eaJUR3Jj44flvPgo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

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