SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e91950bb871cfaf02573fc5dddb3d49ceb2c056d01b4de152d080e9237f6dfa' 
  AND token = 'W+5sexb2RzySVWrxfyIELAC7BkOHCod7maysi8K1ZfY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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