SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '27b3f0becddc3df4a9e31dbb17a3b2a350d033ed25e4b64c37853d92d6ff786a' 
  AND token = '+LiXHtvyaZ3KhVBL65+zVorJL2/hwQ5vJyhAkGzRDA8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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