SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e140c450fbd96dd6fdbc15921249f32aaf3429f5adba51ed99a435ee8e29944' 
  AND token = 'VDElF3JG09z+oHzV8V+A5rCJA9p7ojCjCJ93RBZNsXQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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