SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '73faf4a37a88714beb048735d72c695c0606514a1126ba04ca098ab57955788f' 
  AND token = 'roY1fxG55/rLIL+oFmNqVsJN64bTULECKIZyu/KsfMI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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