SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c318aad3b88220d4aba92b9e0b4cba24d40bb7aa6928394a8b0e742bcbd047c5' 
  AND token = 'Ln4N7GRw37atKFukBWpSoNmSH2NpSnXBz+dOlURMUxM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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