SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd52efc11f0bf9dc2042f5053051e95a549d0fa70ad20f47584bc9368ffcaac5d' 
  AND token = 'hhkSNu2W+2psayrypx93/J3Y2YMJU1pZnAu6Qr8hubg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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