SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '56e2c16f338185f9f9d2e3a1be1237d820b7570c12517c8bf1f0d54d2730eb29' 
  AND token = 'UIvTwgLSqhDwTTa3CEs8nbmI1ucGaj9IydfeD09LbMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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