SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9005ecfe3e78926b27589f9a827188fa45a861f9b7ddc7245c973e73dca20c11' 
  AND token = 'hi6KIt6cdyROuowrtTjOzNIA2gWhUH/iuOjeEhpC6oQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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