SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ffea4d070d26aac8351eae8f9cb9491f0c422402467c79f64ec9d128027b7c28' 
  AND token = '6v71LFbHSLWJdsiZzTGDcBv//Z+yOwGVHIXJ5Bx2kh0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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