SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c6c91bf86d38faa7f4a52640aa92ea26397bdfc047743bb4f009bd0bf41d5e69' 
  AND token = 'Ml0zcihIsMVX6Yx+hFFY/+9FwCeWsCwsZETgSRFaB58=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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