SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e0753152cf3ef84ad4b671765b1e47a5a1e398359f36e012b69d53f9ee9bb09d' 
  AND token = 'l+luLCgwv5AqtaQM8FIMGYAzEPMYmnWCiWOJTOQZhQc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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