SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c03b66ed6d418d3b0f26d43e4bfb7f784dcdd768cf84573295ba29cb3f7d331' 
  AND token = 'bl99xbJIwV7TX7dNqpJsaXFm6rjZRsqFvlCsHcn8STo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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