SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '239063f51dae316ece88284f9a11dc39be04950387d95569a37b57ca47ad69d9' 
  AND token = 'TnP2t2O087OuBwtZlSs+p8LBgzzLDRHrUmW5VpKyqCk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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