SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '51bb57cf1fedf4ebde831ba90c9237a7d670a20bbf939c4c833a1a9f8386b658' 
  AND token = 'UlriUT+S0ji2wv1hZBLvCurmALBCU9VxcSKFs6ij7Qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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