SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3ab4194efc94ba4242d9c367825ead8aacef0209f95818bf422787319dfe3f4' 
  AND token = '8fpC+pJU+AVcF/RvVsej3KYuLexeWnRngBHQJC7FKMc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}