SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '635d844ff69be8a64922e3e364269414b6c874cba6aafef2cd2759364c6213e8' 
  AND token = '2Mx2+NADsLivQGis4ySgdAk4m6LvOCGcJ8DoIji5ujw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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