SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd39e0b9172592212808b2fa1227a7a45c0159935ddc60c06c1ff26723ef802c5' 
  AND token = '34RfK0O6XRqCDgqQDzt0BvQy98hGzbdP8F+6Kf00SkE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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