SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '479b2a05be3d631f134e1e15d95a1efa1621dc7886df99462482af5fad9b88a3' 
  AND token = 'hS1dkq3K6h+z2t3Y5UB+qKIvScL5GNTNg1wJkQeqdXg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00047

JSON explain

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