SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7cf7981dd51bfd55d358b85a14134e5ebcc5b48fe73571751eba61fd31557a2e' 
  AND token = 'fiPG4Wj2LVHDVttvI4k/4BCe0PDuVdn545pWcB1rbcQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}