SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5fdaa882a7e8512f0b603f76336e924734a8b41085e86866ae97272382307d7' 
  AND token = 'VGIezykuWx4rmdfMfTyQwVZUEGBFFsA0s5nXvL9/3i0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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