SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88aa7d5274c83a618dc1aa9edf45b4cbbf78c1696af3d6f0965aed5b7a704201' 
  AND token = 'qValcOwxhW/5YT9jp4bNOhU/PP8FrUBmHehjCp1POww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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