SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f49457cc666113cfc4a61c163662de28b1b6b65d91bbbcaf1f1e10f4d10c5de9' 
  AND token = '+nVeN9p25lI9QbqqRrPZo62XdeQi7+O/k9U9XAC6iYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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