SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '09540e60282e6bdb840d73bbd2b599956311cf320f0199099fde8894622a0fa4' 
  AND token = 'eJ1mhtInIn+DqollrqyZPCxZCTWYqg5/IJVNg3mjsq8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}