SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a09826dd9208eae43884d1ee22a3938ba909d26e14ff0d8037b8597fd7c44268' 
  AND token = 'BU++EDXA9cxROnazo8JTvSrGlqEOAHn7Dm+WSpiqnvE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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