SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '15d7de48ec2b67a50b95450c8934d9e17eafab7f9590abbb1b857cf7f739a621' 
  AND token = 'gDwAUfFZGIL5rCTyJgeBOCzQJQKQ+29YKpi/M7eE/es=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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