SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '10b21533efa6e6012a9f987a686a5570768c4e54fb3640f6be75678c594b82c4' 
  AND token = '2Dyas0FqqTfXWumD1DA62ECIn9mPlRGxXAmmh54z5kk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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