SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '547dd3e85130fe01382533a114508f89d73bec4841aba4365850c17ddb2b1100' 
  AND token = 'XZeJOwvlDoZDACEC9T+3dBnjFLjDDbD8xL9rAOgOGME=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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