SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'aa13d08c2799041fcf13bee329aaa618612c2819d13c50b99e272d45a938ba83' 
  AND token = '9/rV4WdRKUbgFbuKz6VddE8AWBWoFHaM/mnbGtCrqHg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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