SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f9f9b9d0c3086d1c7bcc9e0b5bd83761ebb57a627e7797b306b618eb2a85291' 
  AND token = '1J9/zc+zUpCKNnFiiHDgOptyHUyxhp+qe7j7ILCLm0U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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