SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e9ebd368f63088e516196bf0be6e7be0b5ad69e73478c58d80fefc8462a30d97' 
  AND token = 'MJFivQ0NulgwdofxifuqnWZNohYYJibebeT58AWVDww=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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