SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4f0e840126092986f53628ed4d3ed3739235f12969789e00e799e97095de3b2f' 
  AND token = 'oNva/DKCoLw0hZo9vnKsNg+j79ckIaNmNGPMqcERc7Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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