SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1e826002030dd55b88cd9fd061e65ae28a8bb65247666bdc115e3daf806fc278' 
  AND token = 'R84DLLAHfn/3pQ6l/MbnIB5TpyzBoLEol1ncdE133e4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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